On the original "Eat A Peach" version of "Blue Sky," Dickey Betts and Duane Allman laid down beautifully melodic, catchy solos that guitarists have been mimicking ever since. The overall approach used by both guitarists is to use E major pentatonic (E F# G# B C#) over E and A major pentatonic (A B C# E F#) over A; notice how many common tones there are between these two scales.